A small hand tool for the threaded locking rings that hold a K40's focus lens and mirrors. It replaces the pliers-and-hope method that scratches optics.
Every K40 lens and mirror sits behind a threaded locking ring. The stock method for moving those rings is whatever is in the drawer: pliers, a small screwdriver, a fingernail. All of them slip, and the thing they slip onto is a coated optic that you cannot polish back.
FONLAND made this tool for exactly those rings. It removes and refits the locking ring in the lens tube of a K40 head, and the locking rings on the first, second and third mirror mounts. The handle has a non-slip striped grip, so you can turn a ring with steady pressure instead of stabbing at it.
Why it matters: ZnSe lenses and coated mirrors are soft by workshop standards. One slip of a screwdriver tip across the face leaves a scratch that absorbs laser energy, heats up, and can spoil the optic. A ring tool that engages the ring properly keeps your hands and tools off the glass.
It also helps on the way back in. A ring that is cross-threaded or overtightened can crack a lens or stress a mirror. With the right tool you can seat the ring snug and stop, rather than forcing it with pliers.
If your K40 still runs the original head, check the K40 upgrade order; an air-assist head is usually the first swap, and this tool helps with the lens transfer that goes with it.
| Spec | Value |
|---|---|
| Tool type | CO2 laser lens and mirror nut-removal tool |
| Lens ring | Removes and installs the lens tube locking ring |
| Mirror rings | Removes and installs 1st, 2nd and 3rd mirror locking rings |
| Head fit | K40 small laser head sets |
| Mount fit | K40 laser mirror mounts |
| Designed for | Aftermarket K40 heads and mirror sets |
| Laser type | CO2 |
| Handle | Non-slip striped grip |
| Operation | Manual |
| Package size | 3.9 x 3.9 x 2.36 in |
| Weight | 2.72 oz |
| Versions | Two versions, identical tool |
Lens cleaning is the most common K40 maintenance job, and the one most likely to damage something. Do it with the machine off, on a clean bench, with the tool and a lens tissue ready before you start.
Orientation trips people up. Most K40 focus lenses are plano-convex: one flat side, one curved. The curved side faces up, towards the mirror above. Fitted upside down, the lens still focuses, but the spot is worse and cutting suffers.
Look at the lens while it is out. A clean lens with no pits goes back in; one with a brown burn mark, pitting or a coating that has lifted needs replacing. A replacement such as the Cloudray ZnSe focus lens drops into the same tube if the diameter matches.
Mirrors get dirty more slowly than the lens but just as surely. Smoke creeps up the beam path, and a hazy mirror loses power at every bounce. The FONLAND tool fits the locking rings on all three K40 mirror mounts.
Work on one mirror at a time and do not disturb the adjustment screws on the mount. The ring holds the mirror in the mount; the three screws behind it set the angle. Touch only the ring and you can often clean a mirror without losing alignment.
If you replace mirrors, plan to re-check alignment afterwards. A new mirror can sit a fraction differently in the mount. Wear 10,600nm-rated glasses for the lid-open test fires, and follow the K40 mirror alignment sequence from mirror one outwards. Upgrade mirrors, such as the Cloudray CO2 mirror set, fit the same mounts when the diameter matches.
A beam alignment tool pairs well with this one if you do this job often.
FONLAND describes this tool as made for aftermarket K40 heads and mirror sets, and for K40 small laser head sets and mirror mounts. That covers the common upgrade heads and mounts sold for the K40. It does not promise to fit every ring on every machine.
Look over your parts first:
Both FONLAND versions of the tool are the same item, so there is no size choice to make.
A sensible maintenance rhythm for a working K40, adjusted to how much smoke your materials make:
| Part | Check | Clean or replace |
|---|---|---|
| Focus lens | Before each session | Clean when hazy; replace if pitted or burnt |
| Mirror 3 in the head | Weekly in regular use | Clean when hazy |
| Mirrors 1 and 2 | Monthly | Clean when hazy; re-check alignment after swaps |
| Locking rings | At every clean | Snug, not overtightened |
Acrylic and plywood make more residue than paper or card, so heavy cutting shortens every interval. Keep the tool with your lens tissue and cleaner, so the right tool is always the one within reach. The K40 operating basics fit optics care into the wider routine.
The locking ring in the head's lens tube and the locking rings on the first, second and third mirror mounts.
It is made for aftermarket K40 heads and mirror sets. Compare your stock head's lens ring with the tool's photos before ordering.
Most K40 focus lenses are plano-convex; fit the curved side up, towards the incoming beam.
No. Both are the same FONLAND tool.
Usually not if you only moved the locking ring. Re-check alignment after replacing a mirror.